axle ID help

[Iraqvet05]

I have a bad rear u-joint on my 01' 2500HD 4WD. Several part sites mention there are two axle manufacturers and the joints for each are not interchangeable. How do I identify the manufacturer of my axle? Is the manufacturers name on a tag or do I ID by the bolt pattern on the diff cover? It’s going to be a Spicer or America (AAM) and I have a 4.10 gear…. that’s about all I know.

[95 S_Trucker]

It could be a corporate 14 Bolt, 10.5" ring gear

or a AAM 11.5" Ring gear.

The 14 Bolt will have a removable pinion support, where the 11.5 will not. That is the easiest way to tell them apart.

[Iraqvet05]

After a little more digging, I found I have the corporate 14 bolt (based on the diff cover bolt pattern). Most of the websites I was using state the axle will be a Spicer or AAM but it's not the axle I should have been looking at, it's the driveshaft. I found Spicer stamped into mine near the carrier bearing.

[95 S_Trucker]

spicer will probably be stamped on the driveshaft whether the truck has a 14 bolt or an AAM. You need to know which rear end you have so you can get the proper sized u-joint.

I highly recommend the spicer life u joint. Will outlast anything out there, including precision and moog.

[Iraqvet05]

OK, let me go crawl under the truck again and see what I can find on the axle. This driveshaft site says to check the driveshaft and RockAuto and several others says to check the axle....very confusing.

http://www.dennysdriveshaft.com/c629...78_inches.html

[clinebarger]

If you have a Allison or ZF S6-650 trans.....You have a 11.5" AAM diff.

If you have a 4L80E or a NV4500.....You have a 10.5" 14-bolt (Corporate).

As for identifying U-joint by the axle doesn't sound right to me, I have a 11.5" AAM in my truck, But uses standard Spicer U-joints Not the odd ball AAM joints.

Measure the joints to be sure!